Blogs:

Dan Meyer – http://blog.mrmeyer.com/
Robert Kaplinsky - http://robertkaplinsky.com /
Estimation 180 - http://www.estimation180.com /
Graphing Stories - http://graphingstories.com /
Visual Patterns - http://www.visualpatterns.org/
Andrews Math Space - https://andrewsmathspace.wordpress.com/
Becoming the Math Teacher You Wish You'd Had - http://tjzager.wordpress.com/
Jenise Sexton- Elementary Teacher in Middle School
Graham Fletcher - http://gfletchy.com/
Mike Wiernicki - http://mikewiernicki.com/
Brian Lack - https://brianlack.wordpress.com
NCTM: Mathematics Teaching in the Middle School - http://www.nctm.org/mtms-blog/

Websites:

Illustrative Mathematics - http://www.illustrativemathematics.org/
Emergent Math - https://emergentmath.com/my-problem-based-curriculum-maps/
Teaching Channel & Illustrative Mathematics Partnership: Teacher Collaboration - http://bit.ly/1Kd5ix9
Teaching Channel - http://www.teachingchannel.org
Georgia Virtual Learning Free Resources - http://www.gavirtuallearning.org/
MAP - http://www.map.mathshell.org.uk/index.php
Desmos - https://teacher.desmos.com/
Open Middle - http://www.openmiddle.com/
Bowland Maths - http://www.bowlandmaths.org.uk/index.html
Mathematics Vision Project - http://www.mathematicsvisionproject.org/index.html
LearnZillion - http://learnzillion.com /
Khan Academy - http://www.khanacademy.org/
ShareMyLesson - http://www.sharemylesson.com
Inside Mathematics- http://www.insidemathematics.org/
Annenberg Learner - http://www.learner.org/index.html
Tools for the Common Core - http://commoncoretools.me/
Expeditionary Learning: Center for Student Work - http://elschools.org/student-work
Edutopia – http://www.edutopia.org
Achieve - http://www.achieve.org
Bootstrap - http://www.bootstrapworld.org/materials/spring2016/index.shtml